The present invention relates to an embroidery data creating device for processing an outline data of an original image to create an embroidery data corresponding to the original image.
Presently, there are data creating devices that create embroidery data for use with industrial sewing machines. These data creating devices are computer controlled and are capable of creating high-accuracy embroidery data in a relatively short period of time. Usually these data creating devices are provided with a computer, an image scanner, a hard disk drive, and a CRT (Cathode Ray Tube) display, etc.
Recently, as the performance of personal sewing machines has improved, an embroidery data creating device for use with the personal sewing machine has been sought to satisfy an expanding demand. However, the data creating devices for the industrial sewing machines are complicated, expensive, and are not easy to operate for personal use. Therefore, an inexpensive, easily operable data creating device has been desired. Preferably, such devices are capable of creating embroidery data based on an original, e.g., a freehand line-drawn image drawn on a sheet of paper.
The conventional embroidery data creating devices do not have such a function, and therefore the operator traces an image, which is scanned by the image scanner and displayed on the CRT, with a mouse or the like. Alternatively, a digitizer or the like to create the digital data of the image to the computer should be used. In order to create the high-accuracy embroidery data for stitching a good looking embroidery, a plurality of paths of stitching, and closed regions to be filled with stitches as well as their positions and shapes should be input to the computer.
An embroidery data creating device, which automatically creates the embroidery data, for personal use was disclosed in Japanese Patent Provisional Publication HEI4-174699. The disclosed data creating device is provided with a microcomputer, a small display device, and a keyboard. The device is connected with a monochrome (e.g., black and white) image scanner, and creates the embroidery data as described below.
In this device, firstly the original image is scanned with use of the scanner. Then the scanned image is displayed on the display device. If the displayed image have the desired shape, the embroidery data corresponding to the displayed image is created.
In the embroidery data creating devices of the former type, the operator is required to designate a path of each stitch of the embroidery or to trace the displayed image manually and accurately. It is time consuming, and the larger the image is, the longer time is consumed.
In the embroidery data creating devices of the latter type, the embroidery data creating devices usually deal with a colored image, and do not have a function of processing an outline image or the line-drawn image. Therefore, the embroidery data crating devices of the latter type cannot create sufficient embroidery data, and accordingly the beautiful embroidery may not be produced with use of the embroidery data created based on the line-drawn image. That is, in order to have threads filled in areas defined by the outlines of an image, beseides the data for the outlines, another data for the filled portion should be prepared separately. Therefore, in the latter devices, if a line-drawn image is used as an original data, it is difficult to have sufficient embroidery data.
Generally, there are two methods for dealing with an image pattern, i.e., for scanning the image pattern to generate an image data, and creating the embroidery data based on the image data. First one is to obtain a bit map image by scanning an original image. Then stitching points are determined based on the bit map image. The other one is to pick up an outline data (path data) by scanning the image pattern.
Assume that an image shown in FIG. 16A is to be dealt with (i.e., is to be scanned and then an embroidery data is to be created). With use of the former method, scanning of the image can be achieved relatively easily. However, the stitch usually has only one predetermined direction, and therefore, if the embroidery data creating in accordance with the former method is used for producing the actual embroidery, the produced embroidery would be as shown in FIG. 16B, and the good looking embroidery may not be obtained. Further, in this method, it is difficult to obtain the data indicating application of various methods of stitching to improve an appearance of the embroidery. In order to avoid this problem, a complicated geometric analysis should be made when the image is scanned, and practically it is almost impossible.
According to the latter method, the outline of the image pattern is obtained according to an edge detection algorithm. Since the outlines defining the regions are obtained, the embroidery data for an region defined by the obtained outline data can be made relatively easily. However, if a region defined by an outline has an elongated shape, it is difficult for a processor (e.g., a CPU) to recognize the direction in which the region is elongated. Generally, when a region is to be filled with a thread, the direction of stitching is fixed. If the elongated direction of the region can be determined, it may be possible to change the stitching direction in accordance with the elongated direction. However, since the elongated direction of the region is not easy to obtaine, the fixed direction is to be referred to in order to create the embroidery data for such a region. As a result, if the stiching direction is not appropriate for such an elongated region, the embroidery produced in accordance with the embroidery data created with use of the fixed stiching direction may not be sufficiently beautiful (see portions "NG" in FIG. 16B). To avoid the problem, various algorithms for automatically determining the direction of the stitch have been suggested. However, sufficient result is not obtained yet, and further a large amount of calculation is required in such algorithms. Therefore, the latter method is not applicable to the inexpensive personal use embroidery data creating device.
Further, even if the image pattern to be scanned is an outline image like coloring pictures for children, when it is scanned by the scanner, the obtained image data of the outline has a certain width (i.e., the line is recognized as a two-dimensional area). Therefore, when the image data is processed and the edge of the outline is detected, two outlines are detected at the both ends of the image of the outline as indicated in FIG. 16C. Since the outline is recognized as an area, even if the original is a line-drawn image, it is difficult to assign various method of stitching a line such as a run-stitch, a zigzag stitch, an E stitch and the like.
Therefore, it is not preferable to detect a plurality of lines (i.e., paths of stitching) for a single outline as described above. Preferably, only one path for one line of the original line-drawn image is to be obtained. For this demand, a thinning method which is known as one of the image data processing methods can be used. If a thin line obtained in the thinning method is used as a line defining the path of stitching, the run-stitch, the zigzag stitch, the E stitch and the like can be freely applied (see FIG. 16D). For example, the width of the zigzag can easily be set and/or adjusted if the single thin line is used for defining the paths and/or regions of the embroidery.